well its pretty simple you set it up exactly the same way it is in the sled and there is a drive sproket that has a chain or belt to drive the tracks instead of running that to the tracks you run it to the axle any problems you run in to feel free to ask i helped my buddy build a kart with his 89 polaris as the donor

so just a simple V-belt straight off the primary clutch will work? today i thought for an hour, on how to make a shaft with a pully on it, and on the same shaft have a sprocket, then the chain goes to a sprocket on the axel but i guess just a simply pully on the axel will work fine, haha.
Thanks

If you are looking for something real fast. I would suggest building a setup like the one in the picture (someone posted a link earlier. That has an idler shaft with the original pulley designed for the clutch on the sled engine.

If I understood the discussion right... You are considering running a belt straight form the engines pulley clutch to a plain Jane pulley on the axle. I seriously doubt this will work. The orginal pulley/clutch on you engine is designed to change it's size with RPM. If you don't have a pulley that can absorb that "pull", It may either rip your engine off its mounts, or rip your axle out from under you. However, I am only guessing at this. I have built plenty of snowmobiles but never tried eliminating the secondary pully for a plain pulley). If someone else has tried it and say it will work, You may want to listen to them but my guess are usually right. Keep in mind that if you don't utilize both original pulleys it won't shift the way it was design and will be considerably slower. If you want to do it right and want it to go real fast, mimic that picture. That was a nice setup.

On another note. Single cylinder, two stoke, air cooled snowmobile engines are not designed to run in warm weather. People "cook em" all the time. Old ski doo engines seemed particularly prone to this. If you know what you are doing you can do it though. Don't run the fuel mixture too lean. It will cause a high combustion temp and the air cooled system can't dissapate that much heat. On sleds we would take the cover off if we had to run em on a warm day. Make sure it has plenty of air and possibly you could build an air duct to force air into the fan.

Dude! could you please post that picture again from forum #3 or e-mail it to me at XXXXXXXXXXXX
I'm trying to find a good way as well to mount my 800cc rotax motor to my go cart for the summer, and be able to put it back in the sled when the snow flies!

First time posting. I just ran across this post from google and thought i would see if you were still working on this project. I am doing the same thing and could use some collaboration. i have some ideas to share.

Don,
I'm as far as having an engine, and a bunch of idea's. Trying to figure out what would work the best as far as design ideas, suspension, and of course the whole drive train thing. I have the resources to build just about anything, just waiting for that perfect design to come along. I've been watching a lot of youtube videos to get ideas. If you type in go-cart with snowmobile engine, you'll get tons of results. My biggest concern is modifying the engine so it doesn't get hot. So far I've been thinking, forced air, a large radiator, fan of some sort?? Maybe re-jetting??? Let me know what you think, I'd be glad to share ideas with you throughout our projects.